In the present context brushware is understood to mean all products in which bristle bundles or individual bristles are fastened to a carrier or support having any shape. These can be conventional brushes, such as toothbrushes, body brushes, cleaning brushes, scrubbers, brooms, abrading brushes, polishing brushes, etc. The carrier or support can be a handle, grip or appliance casing, as well as bands, strips, etc., or only preliminary products which are subsequently inserted in a handle, grip, appliance, etc. or are interconnected to form larger units. Bristle bundles are bundles having any appropriate cross-section, e.g. tubular bundles, polygonal bundles, hollow bundles, bundle packs, etc. The bristles are made from plastic, and the thickened portion can be produced by melting the bristle ends and cooling, and optionally by after-shaping.
The aim with plastics brushes was to obviate the previously used mechanical fastening method or the adhesion method. Thus, it is known (DE 845 933), to provide the bristle bundles with a thickened portion, by melting the bristles, and to inject the bristle carrier material around said thickened portion, so as to anchor the bristle bundle in extraction-proof manner in the carrier. This injecting in of the bristle bundle has subsequently been improved (DE 35 11 528, EP 142 885).
In another technology the bristle carrier is provided with preshaped recesses and either melted in the vicinity of the recess and/or the thickened portion on the bristle bundle in a zone close to the surface, and the bristle bundle with the thickened portion is pressed into the recess (U.S. Pat. No. 4,609,228, U.S. Pat. No. 4,637,660). Following insertion the bristle carrier melt flows round the thickened portion, and at the same time there can be a melting together of the plastic components of the bristle bundle and the carrier.
Finally, a thermoelastic joining method is known (U.S. Pat. No. 4,988,146), in which the wall of the recess and/or the thickened portion on the bristle bundle are heated in the zone close to the surface to temperatures below the melting point and subsequently the bristle bundle with the thickened portion is inserted, accompanied by thermoelastic deformation. After cooling the bundle is firmly anchored with the thickened portion in the carrier.
In all these cases heat must be supplied and then removed, which always takes time, so that in these known methods the working cycles are relatively long. In addition, the temperature must be very accurately controlled, so as to avoid thermal damage, particularly embrittlement or thermal oxidation of the polymers. In no case is it possible to prevent deterioration to the molecular structure of the bristles with their often very small diameter.
For special brushes, particularly hair brushes, it is known (DE 937 765) to provide bag-like depressions on a plate-like, rubber-like carrier and to insert in such depressions wire or plastic pins, or also bristle bundles with a thickening at the fastening-side end. On insertion the wall of the bag-like depression elastically gives way and springs behind the thickened portion until it engages on the pin or bundle. Subsequently the plate is marginally fixed in a brush body and curved out, so that it springs through when the brush is in use.